The present invention relates to a scroll-type internal combustion engine for rotating a shaft. More particularly, the present invention relates to an engine having a single orbiting member situated inside an interior volume of the engine to divide the interior volume into a compression chamber for compressing an air and fuel mixture and an expansion chamber for expanding combustion products formed when the air and fuel mixture is ignited. The orbiting member includes an orbiting member plate which is formed to include the aperture means for conducting the air and fuel mixture between the compression and expansion chambers. Valve means is situated on a first stator of the engine to cover the aperture means periodically to regulate flow of the air and fuel mixture in response to movement of the orbiting member with respect to the first stator.
Various types of scroll-type devices are used as fluid pumps, fluid compressors, and as motors or engines to drive crank shafts. It is well known in the art to provide scroll-type engines which include only a single orbiting member that both compresses inlet air and expands combustion products to provide a power take-off for rotating an external crank shaft. See, for example, U.S. Pat. No. 4,677,949 to Youtie et al.
One object of the present invention is to provide a device which is easy to manufacture by designing components which require mating surfaces that may be cast and have the mating surfaces lapped together to achieve a mating seal.
Another object of the present invention is to provide a device having a reliable built-in valving or fluid flow mechanism.
Yet another object of the present invention is to provide a device which utilizes a simple means of transmitting orbiting motion to rotary motion.
Still another object of the present invention is to provide a device which utilizes the energy of centrifugal moment to achieve compression and is not dependent on shaft action for same.
A further object of the present invention is to provide an economical and reliable fuel flow regulating mechanism for a scroll-type engine to simplify manufacture and maintenance of the engine.
According to the present invention, a scroll-type engine for rotating a shaft about an axis of rotation comprises a first stator and a second stator coupled to the first stator to define an interior volume therebetween. An orbiting member is disposed in the interior volume for movement therein. An elongated drive post having a longitudinal axis is seated in the first stator to support the drive post for rotation about its longitudinal axis with respect to the first stator. The engine further includes means on the orbiting member for rotating the drive post about its longitudinal axis and means interconnecting the drive post and the shaft for converting rotational movement of the drive post to rotational movement of the shaft. Orbiting movement of the oscillator imparts rotary motion to the drive post to rotate the drive post about its longitudinal axis. Therefore, the shaft rotates about its axis of rotation in response to movement of the orbiting member within the interior volume as defined by the stators.
The orbiting member includes an orbiting member plate having upwardly and downwardly facing surfaces. The upwardly facing surface mates with the first stator to define a first closed chamber or compression chamber therebetween for receiving an air and fuel mixture therein. The downwardly facing surface mates with the second stator to define a second closed chamber or expansion chamber therebetween. The orbiting member plate is formed to include a hole or aperture at the center as a passage for conducting the air and fuel mixture between the compression and expansion chambers. As the orbiting member goes through its cycle, the aperture formed in the orbiting member plate is moved relative to the first stator so that an interior tip and a scroll located on the first stator alternately uncovers and covers the aperture to open and close the aperture, respectively. Essentially, the scroll on the first stator functions as a valve to control the flow of air and fuel between the compression chamber and the expansion chamber through the aperture formed in the orbiting member plate. This valve action starts and ends both the compression and expansion cycles.
One feature of the present invention is the provision of a scroll-type engine having an orbiting member formed to include aperture means for passing a compressed fuel mixture directly from the compression chamber to the expansion chamber for ignition to provide a power source for rotating the shaft. The engine also includes valve means on the first stator for periodically closing the aperture means to block transfer of the fuel mixture between the compression and expansion chamber in response to movement of the orbiting member to a predetermined position relative to the first stator. Advantageously, such a configuration provides a reliable fuel flow regulating construction which is easy to manufacture and requires less maintenance than conventional scroll-type engines. The present invention does not rely on a fuel injector or the like to add fuel to compressed air in the expansion chamber prior to ignition of the fuel.
Another feature of the present invention is the provision of a drive post coupled to the first stator to extend into the interior volume of the engine. The drive post includes a head portion formed to include an inner wall shaped to define a radially outwardly extending slot. A first portion of the inner wall provides a drive wall for rotating the drive post. A drive pin coupled to the orbiting member is positioned to contact the drive wall to rotate the drive post about its longitudinal axis in response to movement of the orbiting member inside the interior volume relative to the first stator. Advantageously, such a configuration permits the drive pin to reciprocate in the slot along a radius of the drive post and slide along the drive wall as the drive pin is moved in an orbit about the longitudinal axis of the drive post by the orbiting member. Therefore, the orbiting member has a range of movement inside the housing in which the orbiting member rotate the drive post. The orbiting member is not limited to a single orbital path by a rigid connection to the power take-off. Therefore, the spiral wraps of the engine can provide sealed pockets for compressing and expanding the fuel mixture even after some wear occurs inside the engine.
Additional objects, features, and advantages of the invention will become apparent to those skilled in the art upon consideration of the following detailed description of the preferred embodiment exemplifying the best mode of carrying out the invention as presently perceived.